1. Field of the Invention
The present invention relates to a fluorescent display apparatus, and in particular to a fluorescent display apparatus and a method for driving the same capable of providing colorful displays by using a lighting or a display function of a fluorescent display and other emitting means in combination.
2. Description of Prior Art
A fluorescent display tube is an electron tube wherein an electron emitted from a cathode is impacted on a fluorescent film having a voltage applied there to in a vacuum vessel having at least one transparent side to display a character or a figure of a desired pattern. The desired pattern to be displayed is composed of a fluorescent material disposed on an anode.
A general fluorescent display apparatus comprises a glass substrate, a wiring layer for driving an anode or a grid disposed on the glass substrate, a fluorescent film disposed on the anode to have a predetermined pattern, a cathode facing the fluorescent film, the grid disposed between the fluorescent film and the cathode, and an outer glass envelop under a predetermined vacuum condition including a transparent front glass and a side wall formed along an edge thereof disposed between the glass substrate and the front glass.
The fluorescent film which constitutes a fluorescent display has various shapes according to a content to be displayed. When simple alphanumeric characters are to be displayed, a segment type covered with the fluorescent material is employed using a segment as the anode.
In addition, when the characters or the figures are to be displayed, a dot type fluorescent display tube or a graphic type fluorescent display tube is used. Generally, various shapes are displayed according to a dynamic driving wherein a display data is provided to a dot anode electrode.
However, in accordance with a recent progress in fluorescent display technology, a more complex display function is in demand such that various emitting means are simultaneously controlled to correspond to a content to be displayed by the fluorescent display apparatus as well as displaying in color, thereby providing a colorful display.
For instance, FIG. 6 illustrates an example of a fluorescent display tube capable of displaying multiple colors. The fluorescent display tube comprises a plurality of anodes 104 disposed on a surface of a glass substrate 101, a fluorescent film 105 corresponding to the plurality of anodes 104 disposed in a manner that the fluorescent film 105 is spaced apart from the plurality of anodes 104, a grid 106 and a cathode (filament) 107 disposed over the fluorescent film 105. A reference numeral 102 denotes a front glass substrate, and a reference numeral 103 denotes a side wall.
In accordance with the fluorescent display tube, a backlight source 108 is disposed behind the glass substrate 101 and the backlight source 108 comprises a light emitting diode, for instance.
The backlight source 108 of the fluorescent display tube is a surface emitting light source outputting color lights such as a red light, a green light and a yellow light. An area and a brightness of the fluorescent film 105, a position and an area of transparent area and a brightness of the backlight source 108 are determined such that a light 115 of the fluorescent film 105 on a surface of the glass substrate 101, a light 116 of the backlight source 108 passing through an aperture 104a of a strip-type anodes 104 disposed between the fluorescent film 105, and a light 115 of the fluorescent film 105 are mixed when observed by an observer 117.
Therefore, various display modes may be generated according to the color of the backlight source 108 thereby being capable of creating the colorful display modes.
In addition, FIG. 7 illustrates a portion of a display apparatus using a light emitting diode proposed by the applicant, wherein the light emitting diode is disposed in a vacuum vessel as a second light source.
The fluorescent display apparatus 120 is a graphic fluorescent display tube displaying the characters and figures in full color, wherein green (G) and blue (B) are displayed by an illumination of a fluorescent material, and red (R) is displayed by an illumination of the LED 100.
An outer glass envelop of the fluorescent display apparatus 120 comprises a transparent front substrate 121, a back side substrate (not shown) parallel to the front substrate 121, and a side portion (not shown) bonding an edge portion of the two substrates. A plurality of display units 122 is disposed on inner surface of the front substrate 121.
The display units 122 comprises a fluorescent display unit 123 disposed on the inner surface of the front substrate 121 and a LED display 124.
In the LED display 124, the plurality of the LEDs 100 having a predetermined distance therebetween disposed on the front side substrate 121 are aligned along a vertical direction of a display surface to form a row, and the row of the LEDs having a predetermined distance therebetween 100 is arranged in a horizontal direction to form columns.
Pluralities of row wirings 125 and column wirings 126 perpendicular to each other and a drive matrix of the LED display unit 124 are disposed on the inner surface of the front substrate 121. The row wirings and the column wirings are transparent such that the column wirings 126 have a form of a dotted line for successive strip-type row wirings 125 in order to avoid a crossing with the row wirings 125. Accordingly, each of the row wirings 125 is connected to a cathode of each of the LEDs 100, and an end portion of each of the column wirings 126 is connected to an anode of each of the LEDs 100.
In accordance with the above structure, when the row wirings 125 and the column wirings 126 are driven at an appropriate timing, a desired one of the LEDs 100 in an LED display area of the display surface may be selectively illuminated in red.
A wire-shaped control electrode 127 parallel in vertical direction is disposed over the fluorescent display 123 to have a predetermined distance therebetween, and the cathode (filament) (not shown) of strip-type is disposed over the control electrode 127. A reference numeral 130 denotes a transparent insulation layer, a reference numeral 131 denotes the anode, reference numerals 132 and 133 denote a filter and a reference numeral 134 denotes a fluorescent material layer.
The fluorescent display apparatus 120 scans the control electrode and the cathode of each of the LEDs 100 commonly connected using a common scan signal controller. The common scan signal controller provides a display signal to each of the anode 131 of the fluorescent display 123 and the anode of each of the LEDs 100 at a predetermined timing. Accordingly, the fluorescent display 123 and the LED display 124 are synchronizedly driven to display a desired image.
FIG. 8 illustrates a fluorescent display apparatus having an LED as a backlight wherein a light guide plate 141 is disposed on a front surface of the fluorescent display apparatus to produce a profound display.
A FL (fluorescent display) 142, which is a display unit, is attached to a printed circuit board 143 having a circuit thereon for controlling and operating the FL to display an information such as numbers, characters and images while self-illuminating. Specifically, the FL 142 comprises a cold cathode fluorescent tube for instance, to display character and image information of an operating mode such as a time, ‘record’, ‘play’, ‘fast forward’ and ‘rewind’.
In accordance with the display apparatus, a light is attached in a manner that a rectangular portion of the light guide plate 141 corresponds to a display window 144 disposed at an upper portion of a front surface of a front panel, and the FL 142 is attached in a manner that the FL 142 overlaps the illuminator.
The illuminator comprises an LED 145 attached to a left side of the light guide plate 141 having a wedge-shaped cross-section from 4 mm to 1 mm which is fixed to the light guide plate 141 by holders 146a and 146b. 
An illumination of the character and the image displayed in the display area of the FL 142 is recognized from outside by emitting through an area of the display window 144 having a high transmissivity.
A light of the LED 142 is emitted through the front surface for a decoration. That is, the tri-color LED 145 in the illuminator is controlled as well as the display by the self-illumination of the FL to be capable of an illumination of more than seven colors, thereby enabling a display having a whole new lighting different from a conventional liquid crystal display. Contrary to a backlight of the liquid crystal display, a display function itself is not problematic even when a brightness of the illumination of the light guide plate itself is changed due to the self-illumination of the FL.
As described above, when the second emitting means, the light emitting diode for instance, is illuminated simultaneously with the fluorescent display tube in the conventional fluorescent display apparatus, various displays may be provided. For instance, when applied to a fluorescent display apparatus of an automobile, a visibility may be added in order to improve a driving function.
In addition, when various control information of the automobile or a lighting status in the automobile is displayed via an illumination of the LED associated with the fluorescent display apparatus, a colorful display function and a pleasant space may be embodied.
Therefore, in accordance with a conventional technology, an illumination control of the emitting means other than the fluorescent display such as the LED may be simultaneously carried out based on the display data being outputted from a microcomputer of the automobile.
Moreover, while outputting a character data displayed on the fluorescent display tube or a segment selection data from a display controller simultaneously with outputting a portion of the data being outputted from the display controller for the fluorescent display tube as a diode driving signal may be considered, it is disadvantageous in that an illumination output of the LED also changed when the dimming of the fluorescent display tube is carried out.